What's hard, in hacking as in fiction, is not writing; it's deciding what to write. And the vendors of commercial OSes have already decided, and published their decisions.
This has been generally understood for a long time. MS-DOS was duplicated, functionally, by a rival product, written from scratch, called ProDOS, that did all of the same things in pretty much the same way. In other words, another company was able to write code that did all of the same things as MS-DOS and sell it at a profit. If you are using the Linux OS, you can get a free program called WINE which is a windows emulator; that is, you can open up a window on your desktop that runs windows programs. It means that a completely functional Windows OS has been recreated inside of Unix, like a ship in a bottle. And Unix itself, which is vastly more sophisticated than MS-DOS, has been built up from scratch many times over. Versions of it are sold by Sun, Hewlett-Packard, AT&T, Silicon Graphics, IBM, and others.
People have, in other words, been re-writing basic OS code for so long that all of the technology that constituted an "operating system" in the traditional (pre-GUI) sense of that phrase is now so cheap and common that it's literally free. Not only could Gates and Allen not sell MS-DOS today, they could not even give it away, because much more powerful OSes are already being given away. Even the original Windows (which was the only windows until 1995) has become worthless, in that there is no point in owning something that can be emulated inside of Linux--which is, itself, free.
In this way the OS business is very different from, say, the car business. Even an old rundown car has some value. You can use it for making runs to the dump, or strip it for parts. It is the fate of manufactured goods to slowly and gently depreciate as they get old and have to compete against more modern products.
But it is the fate of operating systems to become free.
Microsoft is a great software applications company. Applications--such as Microsoft Word--are an area where innovation brings real, direct, tangible benefits to users. The innovations might be new technology straight from the research department, or they might be in the category of bells and whistles, but in any event they are frequently useful and they seem to make users happy. And Microsoft is in the process of becoming a great research company. But Microsoft is not such a great operating systems company. And this is not necessarily because their operating systems are all that bad from a purely technological standpoint. Microsoft's OSes do have their problems, sure, but they are vastly better than they used to be, and they are adequate for most people.
Why, then, do I say that Microsoft is not such a great operating systems company? Because the very nature of operating systems is such that it is senseless for them to be developed and owned by a specific company. It's a thankless job to begin with. Applications create possibilities for millions of credulous users, whereas OSes impose limitations on thousands of grumpy coders, and so OS-makers will forever be on the shit-list of anyone who counts for anything in the high-tech world. Applications get used by people whose big problem is understanding all of their features, whereas OSes get hacked by coders who are annoyed by their limitations. The OS business has been good to Microsoft only insofar as it has given them the money they needed to launch a really good applications software business and to hire a lot of smart researchers. Now it really ought to be jettisoned, like a spent booster stage from a rocket. The big question is whether Microsoft is capable of doing this. Or is it addicted to OS sales in the same way as Apple is to selling hardware?
Keep in mind that Apple's ability to monopolize its own hardware supply was once cited, by learned observers, as a great advantage over Microsoft. At the time, it seemed to place them in a much stronger position. In the end, it nearly killed them, and may kill them yet. The problem, for Apple, was that most of the world's computer users ended up owning cheaper hardware. But cheap hardware couldn't run MacOS, and so these people switched to Windows.
Replace "hardware" with "operating systems," and "Apple" with "Microsoft" and you can see the same thing about to happen all over again. Microsoft dominates the OS market, which makes them money and seems like a great idea for now. But cheaper and better OSes are available, and they are growingly popular in parts of the world that are not so saturated with computers as the US. Ten years from now, most of the world's computer users may end up owning these cheaper OSes. But these OSes do not, for the time being, run any Microsoft applications, and so these people will use something else.
To put it more directly: every time someone decides to use a non-Microsoft OS, Microsoft's OS division, obviously, loses a customer. But, as things stand now, Microsoft's applications division loses a customer too. This is not such a big deal as long as almost everyone uses Microsoft OSes. But as soon as Windows' market share begins to slip, the math starts to look pretty dismal for the people in Redmond.
This argument could be countered by saying that Microsoft could simply re-compile its applications to run under other OSes. But this strategy goes against most normal corporate instincts. Again the case of Apple is instructive. When things started to go south for Apple, they should have ported their OS to cheap PC hardware. But they didn't. Instead, they tried to make the most of their brilliant hardware, adding new features and expanding the product line. But this only had the effect of making their OS more dependent on these special hardware features, which made it worse for them in the end.
Likewise, when Microsoft's position in the OS world is threatened, their corporate instincts will tell them to pile more new features into their operating systems, and then re-jigger their software applications to exploit those special features. But this will only have the effect of making their applications dependent on an OS with declining market share, and make it worse for them in the end.
The operating system market is a death-trap, a tar-pit, a slough of despond. There are only two reasons to invest in Apple and Microsoft. (1) each of these companies is in what we would call a co-dependency relationship with their customers. The customers Want To Believe, and Apple and Microsoft know how to give them what they want. (2) each company works very hard to add new features to their OSes, which works to secure customer loyalty, at least for a little while.
Accordingly, most of the remainder of this essay will be about those two topics.
THE TECHNOSPHERE
Unix is the only OS remaining whose GUI (a vast suite of code called the X Windows System) is separate from the OS in the old sense of the phrase. This is to say that you can run Unix in pure command-line mode if you want to, with no windows, icons, mouses, etc. whatsoever, and it will still be Unix and capable of doing everything Unix is supposed to do. But the other OSes: MacOS, the Windows family, and BeOS, have their GUIs tangled up with the old-fashioned OS functions to the extent that they have to run in GUI mode, or else they are not really running. So it's no longer really possible to think of GUIs as being distinct from the OS; they're now an inextricable part of the OSes that they belong to--and they are by far the largest part, and by far the most expensive and difficult part to create.
There are only two ways to sell a product: price and features. When OSes are free, OS companies cannot compete on price, and so they compete on features. This means that they are always trying to outdo each other writing code that, until recently, was not considered to be part of an OS at alclass="underline" stuff like GUIs. This explains a lot about how these companies behave.